How to prepare a defeat

French monument for the victory in the First Battle of the Marne (5-12 September 1914) in the First World War. This victory stopped the German invasion and no longer allowed a quick German victory in the war against France.

When Germany invaded Belgium and France in August 1914, it thought that its soldiers would celebrate next Christmas at home, for the war would not last longer. However, the soldiers celebrated Christmas in the trenches, sometimes together with enemy soldiers. This war – the First World War – would last more than four years, and it ruined the German Empire. Also in later wars, it often happened that, before they started fighting, the initiators underestimated the length as well as the possible impact on themselves and their own country, with negative consequences if not outright defeat as the result. Think of the Vietnam War and the wars in Afghanistan. It seems that these mistakes are again made in the wars presently going on in the world. Who would dare to say that the Russian invasion of Ukraine is a success, although on paper Russia should have been able to defeat Ukraine easily? Apparently more is needed to beat a seemingly weak enemy than a stronger army. Again and again we see that, as Monica Duffy Toft says: “Wars are rarely lost first on the battlefield. They are lost in leaders’ minds –when leaders misread what they and their adversaries can do, when their confidence substitutes for comprehension, and when the last war is mistaken for the next one.” But which false decisions if not mistakes can leaders make when they go to war? To gain insight into this, I googled the sentence “how to lose a war”. Below you find a compilation of what I found plus a few factors of my own based on the most recent political developments.

Key factors why a war is lost include:
- Failure of a strategy and lack of clear objectives. Initiating a war without a clear, realistic and achievable goal.
- Strategic miscalculation and overconfidence. Underestimating the opponent and its capability to defend itself and to counterattack. Relying on faulty intelligence or ignoring intelligence. Overestimating one’s own strengths and capabilities. Ignoring the advice of military and political experts and relying too much on the advice of those who are basically on your side. Ignoring dissident opinions. Ignoring warnings of experts of the unintended consequences of your actions, for example for the international markets and economy.
- Prolonged conflict and overreach. Engaging in long, drawn-out struggles that drain military and economic resources and the morale of your own population. Ignoring or underestimating the opposition against the war in your own country.
- Ignoring your allies. Not informing them about your plans, even if you don’t suppose them to participate. Asking them afterwards to correct your mistakes (which they may refuse because “it is not their war”). Not trying to get support from international institutions that might legitimize your actions, or otherwise not informing them about your intentions.
- Attempting to implement “democracy promotion” without local support. Trying to bring a regime change while the local population is mainly on your side but doesn’t have the means or organization to implement such a change and/or doesn’t know what to do for that.
- Alienating the local population and others on your side in or from the enemy country, even if they initially supported you. For example by destroying the infrastructure of the country and its economic capabilities, especially if this destruction will have negative long-term consequences.
- Misunderstanding local dynamics. Failing to appreciate the cultural, historical, and political landscape of the combat zone.
- Too hesitant, too limited use of means to achieve the war objectives. Inconstancy, changeability and capriciousness in the employment of your military and political and economic means.
- Underestimating the enemy’s will to resist.

In short, an initiated war is often lost by underestimating the complexity of the intervention and the enemy’s response. Especially, great powers hold the believe that their abilities will outweigh local complexities. The American senator J. William Fulbright (1905-1995) called it “the arrogance of war”. But even if a war has been well prepared, there still is what Carl von Clausewitz called the “fog of war”: The extreme uncertainty in situational awareness, intelligence, and communication experienced during military operations; the confusion regarding enemy capabilities and intentions. In the fog of war much goes wrong. It often makes a war unpredictable. And even if you have won on the battlefield, it may have made your country so much weaker that we call it a Cadmean victory.

Sources
- When I googled the sentence “how to lose a war”, first I got an AI made compilation of the most important factors that answered my question. However, such an AI survey is dynamic: The next time you google your question, you’ll get a somewhat or completely different reply. In my text I used what I found on 21 March 2026, about 11:00 p.m. This dynamic also made that I cannot refer to the sources this AI survey is based on.
- Amin Saikal, How to Lose a War. The Story of America’s Intervention in Afghanistan.
- Monica Duffy Toft, “How to lose a war”.